In recent years, developments have been made in order to increase protection for vehicle occupants and, in particular, the heads of the occupants when an impact is applied to a side of the vehicle.
A technique has been developed for this type of vehicle occupants protection system in which a roof side airbag is installed, for example, from a pillar to a side edge of a roof of the vehicle, whereby the roof side airbag is caused to inflate along the door windows in such a way as a curtain falls when an impact of a predetermined magnitude or more is applied to a side of the vehicle.
In addition, another technique has been developed for another type of vehicle occupants protection system in which a pillar garnish is mounted on a passenger compartment side of a pillar with a predetermined amount of space being provided therebetween for accommodating therein a small impact absorbing member, so that when an impact of a small magnitude is applied to a side of the vehicle, the impact so applied can be absorbed by the small impact absorbing member.
Furthermore, a technique has been developed in which both the roof side airbag and the small impact absorbing member are provided at the pillar portion. This type of vehicle occupants protection system is known as, for example, an “automotive occupants protection system layout construction” disclosed in Japanese Examined Patent Publication No. 3147172 (hereinafter, referred to as the “related art”). The summary of the related art will be described below with reference to FIGS. 11(a) to 11(c).
FIGS. 11(a) to 11(c) are schematic views of a related art system, and the figures so used here are FIGS. 1, 2 and 4 of Japanese Examined Patent Publication No. 3147172. However, please note that different reference numbers are used. FIG. 11(a) shows a side construction of the system as viewed from a passenger compartment side of the vehicle. FIG. 11(b) shows a cross-sectional construction of the system taken along the line b—b of FIG. 11(a). FIG. 11(c) corresponds with FIG. 11(b) and shows the system after impact.
FIG. 11(a) shows that a bag 104 is installed in a side edge of a roof 102 and part of a front pillar portion 103 of a vehicle 101. The bag 104 is a roof side airbag for protecting the upper bodies of occupants when an impact of a predetermined magnitude or more is applied to a side of the vehicle.
FIG. 11(b) shows that a pillar garnish 107 is mounted on a passenger compartment 105 side of the front pillar portion 103 with a space 106 being maintained therebetween for accommodating therein the bag 104, as well as a rib 108 (corresponding to a small impact absorbing member of the invention) for absorbing an impact of such a small magnitude that the bag 104 remains unopened.
The pillar garnish 107 includes a thick base portion 111 which surrounds the rib 108 and a thin bag accommodating portion 112 which surrounds the bag 104. The base portion 111 is attached to the front pillar portion 103, whereas the bag accommodating portion 112 can be deformed from a proximal end point 113 of the bag accommodating portion 112 to bend towards the passenger compartment 105 side.
A fixing portion 104a of the bag 104, the rib 108 and the base portion 111 of the pillar garnish 107 are bolted together to the front pillar portion 103. A distal end 114 of the bag accommodating portion 112 is elastically supported by an opening weather-strip 115 disposed at a rear half portion of the front pillar portion 103.
As shown in FIG. 11(c), the bag 104 can expand into the passenger compartment 105 while forcibly opening the bag accommodating portion 112 due to gas generated when an impact of a predetermined magnitude or more is applied to a side of the vehicle. As this occurs, the bag accommodating portion 112 deforms from the proximal end point 113 of the bag accommodating portion 112 to the passenger compartment 105 side.
The pillar garnish 107 used in the related art is required (1) to function as an interior material having an impact absorbing construction in an ordinary condition where no impact is applied, (2) to ensure the quick transmission of the impact to the rib 108 when an impact of such a small magnitude that the bag 104 remains unopened is applied, and (3) to deform sufficiently enough when the bag 104 opens that the bag 104 is allowed to inflate quickly and smoothly.
In general, the integration of the rib 108 to the pillar garnish 107 is implemented by attaching the rib 108 to the pillar garnish 107 over the entirety of a bottom surface thereof. This procedure allows the pillar garnish 107 and the rib 108 to be attached to the front pillar portion 103 at the same time.
Only the bag accommodating portion 112, which extends distally from the proximal end point 113 of the pillar garnish 107, is deformed by the force of the expanding bag 104. Since the bag accommodating portion 112 is intended only to surround the bag 104, its length is short, extending from the proximal end point 113 to the distal end 114. The bag accommodating portion 112 deforms in proportion to the amount the bag 104 inflates. Therefore, in order for the short bag accommodating portion 112 to deform significantly, a large magnitude of force must be applied to the bag accommodating portion 112 and, in particular, to the proximal end point 113.
If the bag accommodating portion 112 is made too thin, then it becomes too soft and cannot function sufficiently as an interior material. In contrast, if it is made too thick, then the bag accommodating portion 112 becomes too hard and requires an excessively large magnitude of force to be applied, in particular, to the proximal end point 113. It is not easy to protect the proximal end point 113 against such an excessively large magnitude of force.